50-Year Mortality Trends in Children and Young People: A Study of 50 Low-Income, Middle-Income, and High-Income Countries

Study Questions:

Have causes of mortality changed over the past 50 years among children and young adults?

Methods:

This analysis used data from the World Health Organization (WHO) mortality database. Death rates and causes of death were examined from 1955-2004, for five separate age groups (1-4, 5-9, 10-14, 15-19, and 20-24 years). These data were then stratified by sex. Countries were defined as high income (n = 10), middle income (n = 22), low income (n = 8), very low income (n = 7), and three countries were unclassified. Countries were grouped as Organization for Economic Co-operation and Development (OECD) countries, Central and South American countries, eastern European countries and ex Soviet states, and other countries. Mortality rates were averaged over three 5-year periods (1955-59, 1978-82, and 2000-04). Primary outcomes of interest were communicable and noncommunicable diseases and injury.

Results:

Data were available for 50 countries. In 1955, mortality was highest in the 1- to 4-year age group. Mortality in children ages 1-9 years declined by 80-93% in the 50 years up to 2004, due largely to steep declines in mortality from communicable diseases. All-cause mortality also declined by 68-78% in young people ages 10-14 years in OECD, Central and South American, and other countries. Smaller declines (41-48%) were observed among young men (15-24 years). In 2000-04, mortality in people ages 15-24 years was higher than that in children ages 1-4 years in most countries studied, with the exception of some very low income countries. Mortality in young men (15-24 years) was 2-3 times higher than that in boys (1-4 years). Mortality among young women (15-24 years) was equal to that of young girls (1-4 years) from 2000 onwards. Substantial declines in death caused by communicable diseases were seen in all age groups and regions, although communicable and noncommunicable diseases remained the main causes of death in children (1-9 years) and young women (10-24 years). Injury was the dominant cause of death in young men (10-24 years) in all regions by the late 1970s. Improvements in mortality in young people ages 15-24 years were half that in children, due largely to static or rising injury-related mortality, particularly in young men. Violence and suicide became increasingly important causes of death in young people in the second half of the 20th century, together making up a quarter to a third of mortality in young men ages 10-24 years in all regions by 2000-04.

Conclusions:

The investigators concluded that significant declines in mortality were observed among young children. Adolescents and young adults have benefited from the epidemiological transition less than children have, with a reversal of traditional mortality patterns over the past 50 years. Future global health targets should include a focus on the health problems of people ages 10-24 years.

Perspective:

An examination of mortality trends among the young has significant health implications. These data suggest a need to closely follow mortality rates among adolescents and young adults, and to determine interventions that can prevent certain causes of mortality such as injury.